This method is a shortcut for
.on( "change", handler ) in the first two variations, and
.trigger( "change" ) in the third.
change event is sent to an element when its value changes. This event is limited to
<select> elements. For select boxes, checkboxes, and radio buttons, the event is fired immediately when the user makes a selection with the mouse, but for the other element types the event is deferred until the element loses focus.
For example, consider the HTML: